\\[-1.8ex] Soil Heterogeneity & $-$0.086$^{***}$ & $-$0.075$^{**}$ & $-$0.075$^{***}$ & $-$0.031$^{**}$ & $-$0.033 & $-$0.032$^{*}$ \\ 
  & (0.031) & (0.029) & (0.029) & (0.016) & (0.021) & (0.017) \\ 
\\[-1.8ex] 
Observations & 23,429 & 23,163 & 22,968 & 23,517 & 23,204 & 23,006 \\ 
R$^{2}$ & 0.378 & 0.390 & 0.395 & 0.724 & 0.652 & 0.689 \\ 
